Method of and apparatus for setting blind fasteners

ABSTRACT

Apparatus for setting fasteners having apertures therein, which comprises a mandrel mounted for movement relative to an anvil surface, said mandrel being adapted to receive a fastener thereon by effecting relative axial movement between the mandrel and the aperture in the fastener, means for expanding a portion of the mandrel in front of the fastener to a cross-section greater than the aperture in the fastener, and means for driving the expanded mandrel toward the anvil surface to set the fastener.

United States Patent 1191 Jaffe I METHOD OF AND APPARATUS FOR SETTING BLIND FASTENERS David M. Jaffe, 360 First Avenue, New York, NY.

Filed: Nov. 30, 1972 App'l. No.: 310,789

Related U.S. Application Data Continuation of Ser. No. 142,826, May 11, 1971, abandoned, which is a continuation-in-part of Ser. No. 62,873, Aug. 11, 1970, abandoned.

Inventor:

U.S. Cl. 29/212 D, 29/243.52 1m. (:1 B23q 7/10,,B23p 11/00 Field of Search 29/200 H, 200 B,

29/212 D, 509, 243.52, 200 P; 72/446 X [56] References Cited UNITED STATES PATENTS 2,446,713 8/1948 Melick 72/446 X Oct. 9, 1973 2,605,011 7/1952 Volpe 29/200 11 3,164,283 1/1965 Olson 29/243.52

FOREIGN PATENTS 0R APPLICATIONS 451,396 8/1936 Great Britain 29/200 P Primary ExaminerThomas I-l. Eager Attorney-Marvin Petry [57] ABSTRACT Apparatus for setting fasteners having apertures therein, which comprises a mandrel mounted for movement relative to an anvil surface, said mandrel being adapted to receive a fastener thereon by effecting relative axial movement between the mandrel and the aperture in the fastener, means for expanding a portion of the mandrel in front of the fastener to a cross-section greater than the aperture in the fastener, and means for driving the expanded mandrel toward the anvil surface to set the fastener.

26 Claims, 22 Drawing Figures PATENTED 9 973 SHEET 8 BF 6 Q in .1 A

m nq w PATENTEDUBT elm A 3.763.541

SHEU NF 6 T gLll PATENTED T 9 I973 SHEET 5 OF 6 METHOD OF AND APPARATUS FOR SETTING BLIND FASTENERS This is a continuation of Ser. No. 142,826, filed May 11, l97l, now abandoned, which was a continuationin-part of Ser. No. 62,873, filed Aug. 11, 1970, now abandoned.

BACKGROUND This invention relates to fasteners and more particularly to an improved method of and apparatus for setting blind fasteners.

In many situations it is desired to fasten two pieces of material together when only one side of the work is accessible. When this is to .be effected by a fastener such as a nail or a screw, it is relatively simple to drive the fastener into a fastening position. However, when the nature of the material, or its application, require that a blind rivet or the like be used, difficulties arise in the setting of the fastener, since the work separates the portion of the fastener to be set and the fastening tool.

Many approaches have been taken to overcome this problem. For example, blind rivets have been fabricated with a headed nail thereon, whereupon the rivet is placed in the holes in the work with the head thereof on the far side, and the nail is pulled from the near side of the work, the nail head deforming the far side of the rivet and thus setting the rivet in the work. The nail remains held in the rivet and the portion of the nail protruding from the near side thereof is broken off; Obviously, this is a wasteful and time consuming operation.

In another approach, a plurality of rivets having tapered openings are loaded on a single mandrel having an enlarged head. In operation, the leading rivet and the portion of. the mandrel on which it: is mountedare inserted in the hole and the mandrel is drawn back one rivet length, setting the rivet as it passes therethrough and readying the apparatus for the nextoperation. This is unsatisfactory since rivets must be precisely mounted on the mandrel in a costly and time consuming manner and mandrels have to be replaced after a predetermined number of rivets are set.

In a still further approach, apparatus has been devised wherein the rivet is placed in a hole and a tool including a hook is placed through the. rivet and rotated as it is drawn back, setting the rivet. This approach is also time consuming and costly.

SUMMARY It is, therefore, an object of this invention to provide an improved method of and apparatus for setting blind fasteners.

It is another object of this invention to provide a rivet setting system wherein the setting tool may freely pass through a fastener in a first mode and be operableto set the fastener in a secondmode.

his a more specific object of this invention to provide a rivet setting system including an expandible mandrel wherein in an unexpanded mode the mandrel may receive a fastener thereon for setting and in an expanded mode set the fastener.

It is a still more specific object of this invention'to provide a fastener setting tool including an expandible mandrel mounted for rectilinear movement with respect to an anvil surface and operable to receive a fastener thereon in a first mode and to be expanded such that it is operable to set the fastener thereon when the tool is actuated to move the mandrel relative to the anvil surface.

It is a further object of this invention to provide an improved mandrel assembly adapted to be inserted in one side of a blind fastener and set it from the other side.

It is a still further object of this invention to provide a system wherein a reciprocable member picks up a fastener at one point of its cycle and sets it at another point of its cycle.

It is yet another object of this invention to provide a semi-automatic system for setting a succession of blind fasteners.

In accordance with these and other objects apparatus according to the invention may comprise a mandrel, means for driving the mandrel through a cycle including-forward and reverse portions, means for mounting a fastener on the mandrel prior to the reverse portion of the cycle, and means fo increasing the effective diameter of a portion of the mandrel for at least a portion of the reverse portion of the cycle to set the fastener mounted thereon.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a hand loaded fastening tool according to the invention.

FIG. 2a is an isometric view of a portion of the mandrel assembly shown in FIG. 1 as viewed from line 22 of FIG. 1.

FIG. 2b is an isometric view of a portion of an alternate embodiment of the mandrel assembly shown in FIG; 1 as viewed from line 22 of FIG. 1.

FIGS. 20 and 2d are front views of a third embodiment of the mandrel'assembly shown in FIG. 1.

FIG. 2e is a side elevation view of a portion of the embodiment shown in FIGS. 20 and 2d.

FIG. 3 is a side elevation view of a semi-automatic fastening tool according to the invention.

FIG. 4 is an enlarged side elevation view of a portion of the fastener support sub-assembly shown in FIG. 3.

FIG. 5 is a front view of the fastening tool shown in FIG. 3.

FIG. 6a-6c depicts a cycle of operation of the fastening tools shown in FIGS. 1-5. a

FIG. 7 is a schematic view of a portion of the collar and cylinder of another embodiment of a fastening tool according to the invention.

FIG. 8 shows a development of a portion of the cylinder shown schematically in FIG. 7.

FIGS. '9A-9D show a cycle of operation of the alter nate embodiment of the fastening tool shown in FIGS. Sand 9.

FIGS. 10-12 depict improved fasteners for use with the embodiment shown in FIGS. 7 and 8.

FIG. 13 is an elevation view of a fixture employing features of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the drawings, a preferred embodiment of the invention comprises an expandible mandrel assembly 10 that is adaptable to pass through the hole in a fastener in one mode and to be expanded such that it is operable to set the fastener in a second mode.

The expandible mandrel assembly is shown in connection with a hand loaded tool in FIG. 1, in a semiautomatic hand tool in FIGS. 3-5, and a fixture in FIG.

13. FIGS. 2a-2e disclose three cross-sectional configurations of the mandrel assembly. FIGS. 6a-6c show an operation sequence of the setting of one type of blind fastener by the embodiments of FIG. 1 and FIGS. 3-5. FIGS. 7 and 8 disclose an alternate configuration of the mandrel assembly adapted for the setting of a different type of fastener and usuable with the tools of FIG. 1 and FIGS. 3-5. FIGS. 9A-9D show an operation sequence of the embodiment of FIGS. 7 and 8 and FIGS. 10l2 show three new blind fasteners made possible by the embodiment of FIGS. 7 and 8.

With reference to FIG. 1 of the drawings, a basic hand tool 8 incorporating features of the invention may comprise in a preferred embodiment an expandible mandrel assembly 10 which is connected to a piston 12 mounted for reciprocal movement in a cylinder 14. The expandible mandrel assembly is mounted in a head 16 detachably connected to the rest of the tool 8 and including a chamber 17 therein in axial alignment with cylinder 14. The backward stroke of the piston 12 is powered by a pneumatic-hydraulic operating mechanism l8 and the forward stroke is powered by a spring 22 mounted between the piston 12 and the back of cylinder 14.

The means for reciprocating the expandible mandrel assembly, i.e., the spring mounted piston and the pneumatic-hydraulic operating mechanism, are old in the art and are commercially available. One available tool having these parts is the Gesipa PH-I. Lever and cam type hand tools that perform the same function are also available.

The expandible mandrel assembly 10 that forms a preferred embodiment of the invention includes a shaft 24 connected to piston 12 and reciprocal therewith. The shaft is dimensioned such that a substantial portion thereof extends out of the head 16 through an aperture 26 provided therein, as seen in FIG. 1.

The frong end 28 of shaft 24 is enlarged by a diverging frustoconical portion 30 and then tapered to a point by a conical portion 32. A collar 34 is mounted on shaft 24 substantially to the rear of the front end thereof and within the cylinder 40 for a purpose made clear hereinbelow.

A mandrel expanding member 36 is slidably mounted on shaft 24 and includes a sleeve portion 38 and a hollow cylinder portion 40. The hollow cylinder encloses collar 34 as shown in FIG. 1 and is slidable with respect to the interior wall of chamber 17. With this arrangement, the member 36 is movable along with shaft 24 when collar 34 engages either the front or rear wall of cylinder 40 and is movable with respect to shaft 24 during the initial portions of either a forward or reverse stroke of the shaft 24 a distance equal to the travel of collar 34 within the cylinder 40. A spring 41 is mounted in chamber 17 between the back of cylinder 40 and the back of the chamber.

The forward end of the sleeve 38 is split into a plurality of segments 42, preferably three as shown in FIGS. 2a-2c, but not limited to that number, which are made of strong but flexible material.

The shaft, sleeve, cylinder and collar are dimention 30, will accept the hole in the particular fastener being utilized.

The portion of the shaft extending out of head 16 through aperture 26 is made long enough to accept the fastener at the rear thereof and still have the head of the shaft entirely in front of the fastener. The aperture 26 is of slightly greater diameter than the sleeve 38 such that the shaft and sleeve may freely slide therein. However, the front end of the shaft cannot pass therethrough nor can a fastener mounted on the mandrel assembly.

Upon the actuation of the pneumatic-hydraulic mechanism 18, the shaft 24 will move rearwardly with respect to member 36 the distance of the stroke of collar 34 in cylinder 40. The effect of this movement is to make the segmented end of sleeve 38 ride up on frustoconical portion 30 to increase the effective diameter of the mandrel assembly at this point such that it will not pass freely through the hole in the fastener. The spring 41 assures this expansion of the mandrel assembly upon the initial portion of the rearward stroke of the pneumatic-hydraulic mechanism 18, since it biases the cylinder 40 in the forward portion of chamber 17 while the shaft 24 retracts the collar 34.

Thus, when the collar 34 strikes the rear wall of cylinder 40 and carries the member 36 to the rear along therewith, the mandrel will be operable to engage and set the fastener as the fastener is captured between the expanded mandrel front end and the front of the head 16.

With reference to FIG. 2a, one configuration of the mandrel assembly could include a shaft 24 that is circular in cross-section and a tubular sleeve 38. A tubular sleeve 38 results in arcuate segments 42 which are of a different curvature than frustoconical portion 30 of the shaft. The sleeve material is selected to be resilient enough such that when the shaft is retracted and the segments 42 are caught between the frustoconical portion 30 and a fastener, they will conform to the curvature of the frustoconical portion and set the fastener evenly around its periphery.

An alternate configuration of the mandrel assembly is shown in FIG. 2b and is particularly suitable to applications wherein materials other than metal are being jointed, for example, plastic and/or cloths. The shaft 24' is circular in cross-section, as in the previous embodiment. The back of the sleeve 38 is still tubular, but the segments 42' at the leading portion thereof are triangular in cross-section. When the mandrel assembly assembly of this embodiment is retracted, the edges of the triangular segments engage the fastener and sever the barrel thereof at the far side. This causes the far side of the fastener to curl toward the material and set them.

A mandrel assembly configuration having particular strength is shown in FIGS. 20, 2d and 2e. In this embodiment, the shaft 24" is triangular in cross-section and the segments 42" are in cross-section a secant closing off a circular are that is a portion of a circle circumscribed around the triangle of the shaft. The segments are sized such that the secant is the same length as the length of each side of the triangle and thus, in the unexpanded position of the mandrel assembly, the flats of the three segments are flush with the sides of the triangular shaft and the peripheries thereof form a circle.

The frustoconical portion 30 of this embodiment of the shaft includes triangular flats 44 with their apices adjacent the back of the conical head 32 and their bases leading into the sides of the triangular shaft. Thus, when the shaft is retracted to expand this embodiment of the mandrel, the segments 42" slide up the flats 44 and engage the fasteners for setting at the midpoints of their arcuate periphery, as shown in FIG. 2e.

It is to be understood that, unless otherwise stated, each of the configurations of the mandrel assembly set forth hereinabove is usable in the tools and embodiments described herein, and when the mandrel assembly is mentioned hereinbelow, it is to be taken as being interchangeably one of the configurations shown in FIGS. 2a, 2b and 2c-2e.

The setting stroke of the mandrel assembly is the backward stroke, which is powered by the pneumatichydraulic mechanism 18. The mechanism includes a housing 46 having a pneumatic section 48 and a hydraulic section 50. A piston 52 is mounted in pneumatic section and is driven by a house supply of compressed air delivered thereto through a hose 54 and a port 56. A trigger 58 operates a valve 60 that controls the flow of air to thepneumatic section.

A piston rod 62 is connected to piston 52 and extends through a suitable seal and guide assembly 64 into bydraulic section 50 where it is attached to a piston 66 mounted therein. A upply of hydraulic fluid is contained in the hydraulic section to the left of the piston 66 and in cylinder 14 below piston 12, with a port 68 allowing fluid to flow therebetween. A seal assembly 70 seals head 16 from the hydraulic fluid in cylinder 14.

In operation, upon actuation of the trigger 58, piston 52 is driven to the left as seen in FIG. 1, driving piston 66 along therewith. The velocity of the movement of the piston assembly is controlled by thesize of port 68, but in any event is slowed by the resistance of the hydraulic fluid. The driving of the fluid into cylinder 14 by piston 66 causes piston 12 to be driven back in the cylinder against the bias of spring 22.

A relief port 72 provided in the pneumatic section permits the action of spring 22 to overcome the air pressure in the pneumatic section once the trigger is released and air is no longer being injected therein. The spring drives the piston down in the cylinder I4, the hydraulic fluid below the flange being forced back into the hydraulic section of the housing through port 68 and. moving the piston assembly to the right, as seen in FIG. I. The driving of the piston 12 down the cylinder 14 first unexpands the mandrel assembly and then drives the assembly outwardly.

In FIGS. 6a-6c, the apparatus is shown in operation sequence setting a fastener having a tapered hole wherein the forward portion of the hole is larger than the unexpanded mandrel but smaller than the expanded mandrel. In FIG. 6a the mandrel assembly is in its forward, unexpanded, mode, when the hand tool is picked up for use. A fastener is placed by hand on the portion of the mandrel assembly that extends out of head 16.

The trigger 58 is then operated, driving piston 12 and thus shaft 24 back in cylinder 14 and head 16 respectively. The initial backward movement causes the shaft 24 to move rearwardly with respect to the segments 42 of the mandrel expanding member 36, 'thus expanding the effective cross-section of the head of the mandrel, as discussed in detail hereinabove. Continued backward movement of the shaft 24 causes collar 34 to drive the entire mandrel assembly to the rear, whereupon the expanded head of the mandrel engages the far side of the fastener and sets it (FIG. 6b).

The leading portion of head 16 is flat such that the head of the fastener is flush therewith and provides an anvil" when the expanded mandrel exerts its rearward force against the front of the fastener. With the type of fastener shown in FIGS. 6a-6c, after setting the front of the fastener, the mandrel then reaches the portion of the hole where the diameter thereof is greater than the expanded mandrel. The mandrel assembly then retracts until the enlarged head portion engages aperture 26, which will not pass it through. The trigger is then released, allowing the mandrel assembly to unexpand and return to its start position where it can accept another fastener for setting.

In addition to setting a fastener having a tapered hole, the pneumatic-hydraulic tool 8 is operable to set an eyelet type of fastener. An eyelet fastener includes a flange and a barrel having a hole of constant diameter therethrough. As stated hereinabove, one widely used method for the blind setting of eyelet fasteners is to equip it with a headed nail, the head of the nail being in the front of the barrel and the shank of the nail being in the front of the barrel and the shank of the nail extending from the flange end. The eyelet is set by grasping the shank of the nail and pulling it to the rear, thus forcing the head of the nail back into the barrel of the eyelet to deform and set it. The portion of the nail shank protruding from the flange of the eyelet is then severed and disposed of.

The use of the expandible mandrel assembly and the tool 8 to set the eyelet fastener completely eliminates the need of equipping it with the headed nail and the resultant saving in time and material cost is manifest.

In operation, the eyelet is placed on the portion of the unexpanded mandrel assembly extending from the head 16, the thus loaded mandrel is placed in the work and trigger 58 is actuated. The mandrel assembly is first expanded and then driven back into engagement with the front of the eyelet, deforming and pressing the front thereof back intothe work. The flat front of head 16 forms an anvil for the setting process.

Upon release of the trigger 58, the spring 22 first unexpands the mandrel and then returns the mandrel assembly to the start position. The unexpanded man drel is then removed through the hole in the set fastener by moving the tool 8 away from the work.

With reference to FIGS. 3-5 of the drawings, a preferred embodiment of a semi-automatic fastening tool according to the invention generally comprises a housing 74 having therein a pair of axially aligned cylindrical chambers 76 and 78 separated by a wall 80. A fastener supply assembly 82 supplies fasteners one at a time into chamber 76 through an escapement mechanism 84, a support 86 retaining the fasteners in position in the chamber 76.

A mandrel assembly 88 similar to mandrel assembly 22 is supported in wall and is reciprocated by a drive arrangement 90 mounted in chamber 78 such that the mandrel assembly is operable to pick up a fastener on support assembly 86, carry it out through a nose 92 mounted at one end of housing 74 in communication shaped cross-section for receiving the flanged portion of the fasteners. The thickness of the cross bar of portion 102 is greater than the thickness of the flanges of the fasteners so that the fasteners can arrange themselves in a line with the flanges thereof overlapping. The back of the T-shaped portion 102 also extends into the chamber 74 for preventing fasteners from falling backwards in the chamber and includes a cut out portion 104 so that the mandrel assembly can pass therethrough.

The escapement mechanism 84 is operable to provide one fastener at a time from the supply assembly into chamber 76 through an opening 106 in housing 74 in a predetermined relationship with the cycle of the mandrel assembly. The escapement mechanism includes a first slat 108 mounted for slidable movement in the housing wall to and from a position whereat the leading edge thereof blocks the chute 100. A spring 110 connected at one end thereof to the housing and at the other end thereof to the slat biases the slat 108 in its closed position. The slat 108 includes a portion 112 angled into chamber 76 so as to be in the path of the mandrel assembly as it reciprocates.

A second slat 114 is mounted for slidable movement in the housing wall and includes a stop bar 116 supported by a vertically extending member 118. The slat 114 is movable to and from a normal position whereat stop bar 116 blocks chute 100 at a point spaced approximately one fastener thickness above slat 108. A portion 120 of slat 114 is angled into chamber 76 so that it may also be engaged by the mandrel assembly and a spring 122 mounted between the slat and the housing biases the slat into its blocking position.

The slats 108 and 114 are operated alternately by the mandrel assembly as will be discussed more fully below such that a single fastener is released into chamber 76 prior to each forward stroke of the mandrel assembly.

The support assembly 86 includes a fastener support tray 124 having a fastener barrel support 126 and an arcuate camming surface 128 connected to each of the sides thereof. The tray 124 is pivotally mounted on a pin 130 for movement downwardly into a recess 132 provided therefor in housing 74. A spring 134 biases the tray into its upward position.

A fastener gated through the escapement mechanism 84 falls onto tray 124 where it rests as shown in FIG. 4, i.e., with its barrel on support 126 in spaced relationship with the mandrel assembly and the flanged end retained in place by the bottom of chute 100. When the mandrel assemblypicks up the fastener and carries it forward, the flanged end will engage camming surface 128 forcing the tray into recess 132 to allow the flange to pass the support assembly.

The nose 92 includes a plurality of tapered segments 136 that are hinged to the housing by spring connections 138 such that the nose is biased into its closed position shown in solid lines in FIG. 3. The front of each segment is flanged and cut to form a flat nose front having an aperture 140 therein. The diameter of aperture 140 is slightly larger than the largest diameter of the mandrel assembly in its unexpanded mode, but smaller than that of the mandrel nose assembly in its expanded mode.

The mandrel assembly 88 is similar to that described in the previous embodiment and the same numerals are used to indicate the same parts. The shaft 24 and mandrel expanding member 36 of this embodiment are somewhat longer than in the previous embodiment and have a greater re-ciprocatory stroke. In addition, a plurality of fingers 142 are mounted on the shaft a predetermined distance from the front end thereof and extend radially therefrom through the splits in the sleeve 38 between segments 42.

The mandrel assembly is reciprocated by the drive arrangement which includes a piston 146 mounted for slidable movement in chamber 78 and having a piston rod 148 extending therefrom and connected to shaft 24. A spring 150 is mounted between the piston and the back end of chamber 78. An air duct 152 enters chamber 78 at the front thereof and communicates with an air hose 154 that is connected in turn to a house supply of compressed air. A valve 156 controls the flow of air to the chamber 76 and is actuated by trigger 94 on grip 96.

A pair of relief valves 158 and 160 mounted in ports 162 and 164 respectively are provided in housing 74 to port the air in chamber 78 on both sides of piston 146 to the atmosphere when the piston is driven toward the respective ducts.

The length of chamber 78 and thus the stroke of piston 146 is selected such that, upon the forward stroke of the piston, fingers 142 are flush with the front of nose 92. A plurality of cutouts 165 are pro-vided in the nose segments 136 to accommodate the fingers 142 therein.

Referring now to FIGS. 3-5 and 6a-6c, in operation, the tool as seen in FIG. 3 is near the start of its forward stroke, which is powered by spring 150. A fastener is in place on support assembly 86 since on the last portion of the back stroke of the previous cycle the back of the cylinder 40 engaged the angled portion 112 of slat 108, retracting it against the bias of spring 110 to allow the bottommost fastener to fall into chamber 76 and onto the support assembly 86.

As the mandrel assembly is driven forward, it passes through the cut-out portion 104 in chute 100 and the hole in the fastener, the fastener being picked up by the fingers 142 and resting on sleeve 38. As the mandrel assembly proceeds still further forward, the leading edge of cylinder 40 engages angled portion 120 of slat 114 and carries the slat forward against the bias of spring 122 to allow the stack of fasteners to drop onto slat 108, which has been returned to its closed position by spring 1 10 as the mandrel assembly moved forward.

The leading portion of the mandrel assembly with the fastener thereon now exits through the nose 92, the head of the fastener camming open the nose segments to allow the fastener loaded mandrel assembly therethrough. The spring connections 138 close the nose behind the head of the fastener, and the fastener is placed in the hole in the work, see FIG. 6a.

After the fastener has been placed in the work trigger 94 is depressed, opening valve 156 to permit compressed air to drive piston 146 back in the chamber 78. The initial portion of the back stroke retracts the shaft 24 with respect to sleeve 38 to expand the mandrel, in the manner set forth hereinabove in connection with the embodiment shown in FIG. 1, to beyond that of the forward end of the fastener.

Thus, when the collar 34 strikes the rear of cylinder 40 and causes the entire mandrel assembly to retract, the sleeve segments 42 will engage and flare the front end of the fastener, the nose front acting as an anvil, supporting the head of the fastener as the sleeve segments exert its rearward force on the front of the fastener (FIG. 6b) and, as the expanded mandrel front portion reaches the portion of the fastener having a larger hole cross-section than itself, the mandrel assembly passes through the fastener, back through the nose, which is cammed opened by the frustoconical surface of the mandrel assembly, and into chamber 76, leaving a set fastener (FIG. 60).

As the mandrel assembly approaches the position shown in FIG. 1 the spring 122 forces slat 1 14 back into the chute 100 to support all the fasteners therein except the lowermost one and then the back of cylinder 40 will engage the angled portion 112 of slat 108 and drive it back, allowing the bottommost fastener to fall into support assembly 86 for the next cycle. The initial portion of the nextforward stroke drives collar 34 forward in cylinder 40 to unexpand the mandrel assembly prior to the forward stroke of the assembly towards and out the nose 92.

With reference to FIGS. 7, 8 and 9A-9D, an alternate embodiment of the invention involves a modified shaft collar, designated 34, operating in a modified cylinder, designated 40. The modified shaft collar 34' includes two diamond shaped key members 166 adapted to move in a keyway 168 formed in the inner face of cylinder 40'. The configuration of keyway 168' is best seen in FIG. 8, which is a development of the cylinder 40'. All other elements of this embodiment of the invention are the same as the embodiment described hereinabove in connection with FIGS. 3-5 and are designated by the same numerals.

The operation sequence of the fastener system of this alternate embodiment is a four stroke cycle wherein eyelet type fasteners can be set. At the beginning of the cycle, the spring 150 drives the mandrel assembly 22 forward, picking up a rivet from the feed and support assemblies and driving the fastener out the nose of the tool in a manner identical to the embodiment of FIGS. 3-5. At this time, the fastener and mandrel are placed in the hole in a piece of work, as seen in FIG. 9A.

The trigger 94 is then'depressed, sending compressed air into the front of chamber 78 and driving piston 146 backwards. Initially, this drives collar 34' back in cylinder 40', with the key members 166 moving back in keyway 146 from the points designated A in FIGS. 7 and 8 to the points designated B, or all the way to the back wall of the cylinder.

This expands the mandrel, since the frustoconical shaft portion 30 of the mandrel retracts with respect to sleeve 38 in the same manner as discussed hereinabove to increase the diameter of the head of the mandrel to beyond that of the hole in the fastener. Further backward travel of piston 146 drives the expanded mandrel back into the leading edge of the rivet, with the frustoconical shaft portion 30 setting the leading edge of the fastener, as seen in FIG. 9B. The backward travel of the mandrel assembly back through the fastener and the nose, as in the system of FIGS. 60-60, is precluded by the obstacle presented by the set fastener acting against the sloping wall of the expanded mandrel.

The third stroke of this embodiment involves releasing the trigger, causing a forward stroke 'as the spring again drives the piston forward in chamber 16 once the air starts escaping from port 106. The effect of this forward stroke is to drive collar 34 forward in cylinder 40' with the key members 166 moving along the keyway 168 from points B to points designated C, which drives the collar to the front of the cylinder, unexpanding the mandrel.

This prepares the mandrel assembly for withdrawal through the rivet back into the tool. This is the effect of the fourth stroke of the cycle, which is caused by again depressing the trigger 94 and driving the piston 146 backwardly. The initial effect of this backward stroke is not to expand the mandrel, since the collar 34' moves backwardly in cylinder only slightly. This is due to the key members moving in the keyways only from the points C to the points designated points D. Thus, the backward movement of the collar 34' with respect to the cylinder 40' is halted near the front of the cylinder and then the entire mandrel assembly is withdrawn through the rivet back into the housing 74 as the piston travels back towards the back wall of chamber 78, readying the system for the next cycle on the next forward stroke of the piston.

It will be noted that in this embodiment, there is a provision for the collar to move backward in the cylinder a small amount, seen most clearly in FIGS. 9A and 9C, without expanding the mandrel. The length of this amount is equal to the longitudinal element of the length of travel of the keys in the keyway portion C-D and is provided so that the mandrel assembly will be unexpanded during stroke four so that it may come back freely through the rivet.

The advantages of this four stroke system are manifest. The eyelet type fastener and others like it having a hole of constant diameter are the most desireable to use in many applications due to their strength and low cost. Heretofore it has been particularly costly and difficult to set these type of rivets in blind situations and impossible to set them with a strong set. Now, with the modified collar and cylinder shown in FIGS. 7 and 8, the semi-automatic tool of FIGS. 3-5 may be used to set this type of fastener. As described hereinabove, the hand fed tool of FIG. 1 is also operable to set the eyelet fastener, using a two stroke cycle.

This embodiment also permits the employment of special blind fasteners, such as those shown in FIGS.

10-12. Referring to FIG. 10, a water tight fastener comprises the usual head portion 172 and a barrel portion 174 that is closed at the far end thereof and includes a crimped portion 176. The inner diameter of the crimp 176 is selected such that the unexpanded mandrel of the embodiment shown in FIGS. 7, 8 and 9A-9D can pass therethrough. Thus, when the mandrel is expanded and withdrawn, the sleeve segments 42 will engage the far side of the crimp and set the rivet against the far side of the work.

With reference to FIG. 11, this embodiment of the invention makes a threaded blind rivet possible. One such rivet, designated 180, includes the usual head por tion 182 and a barrel portion 184 that includes a threaded portion 186 and an unthreaded portion 188. The expanded mandrel will set the unthreaded portion, leaving the threaded portion intact since the inside diameter of the threading is selected to permit the unexpanded mandrel to freely pass therethrough.

FIG. 12 depicts a crimped, threaded rivet 190 that combines the features of rivets 170 and in that it includes a crimped portion 192 and a threaded portion 194, resulting in a water-tight, threaded rivet.

With reference to FIG. 13, the fastening tool shown in FIGS. 3-5 can be mounted in a fixture 200 including a fastening tool housing 202 that corresponds to housing 74 of the embodiment of FIGS. 3-5. The fixture includes a Syntron type feed 204 to the escapement mechanism 84 (not specifically shown) in the fixture housing wherein fasteners are fed to the mandrel assembly mounted in the housing for reciprocal motion out the fixture nose 206, identical to nose 92, in the same fashion as the semiautomatic tool shown in FIGS. 3-5. An anvil 208 having an aperture therein mounted for up and down movement on a support 210 that is raised and lowered by an air cylinder 212.

The operation of air cylinder 212 is in timed relationship with the mandrel assembly drive such that the anvil is raised on the downstroke of the mandrel assembly, wherein the fastener on the mandrel assembly is either placed in a prepared hole in the material, or a hole in the material is made for the fastener by the mandrel conical portion 32 on the downstroke of the mandrel. the rearward stroke of the mandrel assembly then sets the fastener as set forth hereinabove in connection with the embodiment shown in FIGS. 3-5.

This fixture is most suited to the fastening of two pieces of cloth, of cloth to plastic, or of two pieces of like soft material, and thus the mandrel expanding sleeve embodiment of FIG. 2b would be most suited thereto.

Having now fully set forth both structure and operation of preferred embodiments of the concept underlying the present invention, it may be that various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will occur to those skilled in the art upon becoming familiar with said underlying concept. For example, it will be apparent to one skilled in the art that the mandrel assembly utilized in all of the embodiments described hereinabove is fabricated of a hard material having a high tensile strength such as maraging steel, such that it is operable to set many tens of thousands of fasteners, which are, by their nature, fabricated of relatively soft deformable materials.

This difference in the relative hardness of the mandrel assembly and the fasteners coupled with the power of the various drive mechanisms disclosed provides a capability to the invention of setting a fastener without passing the mandrel assembly completely through the aperture therein.

The mandrel need only be inserted into the fastener to a position where the enlarged head thereof is past the portion of the fastener barrel that is located interior of the work. The subsequent expansion of the mandrel distends the barrel of the fastener and, when the expanded mandrel is driven toward the anvil, the barrel of the fastener distends back to the work, setting the fastener.

When the method of the invention is practiced in this manner, it can be used to set fasteners having a substantially uniform cylindrical barrel with a closed end to provide an inexpensive weatherproof fastening.

It will be evident that in the practice of this last named method that if the mandrel assembly had initially been precisely located with respect to the work such that the barrel of the fastener is distended back to the work by the initial expansion of the assembly, the step of driving the assembly toward the anvil is omitted since a set fastener blocks rearward movement of the mandrel assembly.

In a modification of this last named method, the mandrel assembly can be inserted into the fastener aperture at the barrel end thereof and expanded to set the fastener.

Furthermore, several alternative constructions and modes of expanding the mandrel assembly 10 are readily suggested to one skilled in the art. For example, referring to FIGS. 2c-2e, it will be apparent that the expansion of the effective cross-section of the mandrel assembly could be effected by the reverse of the elements shown. More specifically, the expansion of the effective cross-section of the mandrel assembly shown in FIGS. 2c-2e could be effected by utilizing a triangular shaft 24" without the enlarged head portions 30 and 32, lengthening the segments 42 so that they protrude in front of the end of the shaft 24" and thickening the protruding ends. The thickened segment end portions are in cross-section a segment 42" such as shown in FIGS. 2c-2e with a rectangular portion contiguous to the secant side thereof, the height of the rectangle increasing from zero at the position on the segments where the leading end of the shaft is positioned in the unexpanded mode to a maximum at the tips thereof.

With this arrangement, assuming the drive mechanism has also been reversed to withdraw the segments initially rather than the shaft, the segments are withdrawn to expand the mandrel and then the assembly as a whole is driven to the rear. The expansion of the mandrel is caused by the thickened segment end portions riding up onto the shaft, the effect being to move the circular sides of the segments outwardly to set the fastener.

These and all other such embodiments, variations, and modifications that incorporate the spirit of the invention and depend upon its underlying concept are consequently to be considered as within the scope of the claims appended herebelow, unless the claims by their language expressly state otherwise.

I claim:

1. Apparatus for setting fasteners having apertures therein, which comprises:

a mandrel assembly adapted to be expanded from an unexpanded mode to an expanded mode mounted for movement relative to an anvil surface, said mandrel assembly being adapted to receive a fastener thereon in its unexpanded mode by effecting relative axial movement between the mandrel assembly and the aperture in the fastener, the mandrel assembly in its unexpanded mode occupying substantially the entire cross-sectional area of the aperture in the fastener when the fastener is received thereon,

means for expanding the mandrel assembly to its expanded mode wherein a portion thereof has a cross-section greater than the aperture in the fastener, and

means for driving the expanded mandrel assembly toward the anvil surface to set the fastener.

2. Apparatus according to claim 1, wherein:

the mandrel assembly includes a shaft having an enlarged front portion.

3. Apparatus according to claim 2, wherein the enlarged front portion of the shaft includes a tip tapered to a point from a base having a cross-section larger than that of the shaft and a portion of decreasing crosssection between the base of the tapered tip and the shaft proper.

4. Apparatus according to claim 2, wherein the means for expanding the mandrel assembly includes a sleeve of resilient material mounted for slidable movement on the mandrel to and from a position whereat the leading edge thereof is mounted adjacent the thickest part of the enlarged front portion thereof, said sleeve being segmented adjacent the leading edge thereof.

5. Apparatus according to claim 4, wherein:

the mandrel shaft is circular in cross-section and the enlarged front portion of the mandrel includes a tapered conical tip and a frustoconical portion of decreasing cross-section between the base of the conical tip and the shaft, and

the sleeve is tubular and the segments thereof are in cross-section sections of an annular ring.

6. Apparatus according to claim 4, wherein:

the mandrel shaft is circular in cross-section and the enlarged front portion of the mandrel includes a tapered conical tip and a frustoconical portion of decreasing cross-section between the base of conical tip and said shaft, and

said sleeve is tubular and at least portions of the segments thereof are triangular in cross-section, one apex of the triangle being pointed radially outwardly to engage and sever the endof the fastener.

7. Apparatus according to claim 4, wherein:

at least a portion of the mandrel shaft is of triangular cross-section and theenlarged front portion of the mandrel includes a tapered conical tip and asubstantially frustoconical portion of decreasing crosssection between the conical tip and the triangular cross-section, the substantially frustoconical section including triangular flats faired into the sides of the triangular shaft, and

the sleeve segments are secant sections ofa circle circumscribed about the triangle ofthe shaft crosssection.

8. Apparatus for setting fasteners having apertures,

comprising:

a housing including an anvil surface with an aperture therein,

a mandrel assembly mounted in said housing and extending out of said aperture, said mandrel assembly being adapted to be expanded from an unexpanded mode to an expanded mode and to receive a fastener thereon in its unexpanded mode for setting by effecting relative'axial movement between the mandrel assembly and the aperture in the fastener, the mandrel assembly in its unexpanded mode occupying substantially the entire aperture in the fastener when the fastener is received thereon,

means for expanding the mandrel assembly on the side of the fastener away from the anvil surface to a cross-section greater than the diameter of the aperture in the fastener, and

means mounted in said housing for driving said expanded mandrel assembly relative tosaid anvil sur face to set the fastener, said means including a cylinder and a piston reciprocal in the cylinder and connected to said mandrel assembly.

9. Apparatus according to claim 8, wherein:

said mandrel assembly includes a shaft having an enlarged front portion, and

the means for expanding the mandrel assembly includes a sleeve having a segmented front portion, said sleeve being mounted on themandrel shaft for movement relative thereto and from a position whereat at least a portion of the segmented front thereof is adjacent the thickest part of the enlarged front portion of the mandrel shaft such that the thickness of the sleeve segments is added thereto.

10. Apparatus according to claim 9, wherein the means for moving the sleeve relative to the mandrel shaft includes an enlarged portion provided on said sleeve at the rear thereof and a collar mounted on said mandrel and movable within said enlarged sleeve portion upon the rearward movement of the piston.

11. Apparatus according to claim 8, wherein:

a chamber is provided in said housing between said anvil surface and said cylinder, said chamber communicating with said aperture in the anvil surface.

said mandrel assembly includes:

a shaft portion extending from the piston through said chamber and out said aperture,

an enlarged front portion mounted on the end of the shaft portion extending from the aperture, and

a collar portion mounted on the shaft portion in said chamber,

said means for expanding the mandrel assembly includes a member mounted for slidable movement with respect to said shaft and having a sleeve portion with a segmented front end extending through said aperture to a position normally adjacent the enlarged front portion of the mandrel shaft and a hollow, enlarged portion connected to said sleeve portion and mounted for movement in said chamber, said hollow enlarged portion enclosing said collar on the shaft,

' rearward movement of the piston being operable to first expand the mandrel assembly as the enlarged shaft portion is moved relative to the sleeve segments and the latter surround at least a portion of the enlarged front end, adding their thickness thereto, and

further rearward movement of the piston being operable to drive the expanded mandrel assembly into the fastener as the collar strikes the rear of the ho]- low enlarged portion of the expanding member and carries it to the rear along therewith.

12. Apparatus according to claim 9, wherein said driving means further includes a spring mounted between the back of the piston and the back of the cylinder to bias the enlarged front of the mandrel shaft away from said anvil surface and means for admitting fluid to said cylinder in front of said piston to expand the mandrel assembly by causing movement of the sleeve relative to the mandrel shaft and to drive the expanded mandrel assembly toward said anvil surface. 7

13. Apparatus according to claim 11, wherein the shaft portion of the mandrel is circular in cross-section and the enlarged front portion of the mandrel shaft includes an enlarged conical tip and a frustoconical portion of decreasing cross-section between the base of the conical tip and the shaft.

14. Apparatus according to claim 13, wherein:

said chamber is cylindrical, said sleeve is tubular, said segments are arcuate in cross-section and the leading edges thereof are flared outwardly, and

the enlarged portion of the expanding member is m bular with front and rear walls slidable on the mandrel shaft portion, the tubular periphery being slidable in said cylindrical chamber.

15. Apparatus for setting fasteners having apertures therein, which comprises:

a housing,

a nose mounted at one end of the housing, said nose including an anvil surface having an aperture therein,

a mandrel mounted for reciprocal movement in said housing,

means for loading a fastener on the mandrel,

means for driving the mandrel through a forward stroke wherein the portion thereof having the fastener loaded thereon extends out the nose,

means for expanding the effective cross-section of the end portion of the mandrel beyond that of the fastener aperture after the forward stroke of the mandrel, and

means for driving the expanded end of the mandrel toward said anvil surface to set the fastener.

16. Apparatus according to claim 15, wherein:

said mandrel includes a shaft portion and an enlarged front portion, and

said means for expanding the mandrel includes a sleeve mounted for slidable movement on the shaft for movement to and from a position adjacent the thickest part of the enlarged front portion of the mandrel.

17. Apparatus according to claim 15; wherein said nose includes:

a plurality of segments hingedly mounted to the housing, and

means for biasing said nose segments to a position wereat they are operable to pass the fastener loaded mandrel therethrough from the housing out, but only to pass the mandrel therethrough into the housing, thus providing the anvil surface for the setting of the fastener.

18. Apparatus according to claim 15, wherein said means for loading a fastener on the mandrel includes:

means for supporting the fastener in said housing wherein the aperture therein is in spaced relationship with the mandrel, and

means for gating a fastener onto said support in a timed relationship with the reciprocal movement of the mandrel.

19. Apparatus according to claim 15, wherein said means for driving said mandrel includes a cylinder provided in said housing, a piston mounted on the mandrel and reciprocal in said cylinder, a spring mounted between the back of the cylinder and the back of the piston for driving a portion of the mandrel out of the nose and means for admitting compressed air into the cylinder in front of the piston to set the fastener on the portion of the mandrel extending out of the nose and drive the mandrel portion back inside the housing.

20. Apparatus according to claim 16, wherein said means for expanding the mandrel further includes:

a tubular member mounted to said sleeve at the rear thereof and slidable along therewith on said mandrel, said tubular member including a front and a back, and

a collar mounted on said mandrel and within said tubular member wherein initial driving movement of the mandrel effects the expansion of the end portion of the mandrel since the segmented end of the sleeve moves to said position adjacent the thickest portion thereof and when the collar strikes the rear of the tubular member the thus expanded mandrel is driven back into the fastener.

21. Apparatus according to claim 6, wherein said mandrel shaft conical portion includes a sharp tip for puncturing apertures in work for the receiving of fasteners therein.

22. An apparatus for setting fasteners having apertures therein, which comprises:

a mandrel mounted for movement relative to an anvil surface, said mandrel including a shaft having an enlarged front portion, at least a portion of the shaft being of substantially polygonal cross-section and the enlarged front portion of the mandrel including a generally frustoconical portion of decreasing cross-section between the leading edge thereof and the polygonal cross-section portion of the shaft, said generally frustoconical section including flats faired into the sides of the polygonal shaft, sleeve mounted on the mandrel, the front portion of said sleeve being segmented, said sleeve segments having generally flat interiors disposed opposite the sides of the polygonal cross-section portion of the shaft, means for sliding said sleeve relative to the mandrel to and from a position whereat the leading edge of the sleeve is positioned on the enlarged front portion at a point whereat the effective cross-section of the mandrel and sleeve segments are greater than the aperture in the fastener, the generally flat interior of the sleeve segments sliding on the flat of the frustoconical portion of the mandrel, and

means for driving the expanded mandrel towards the anvil surface to set the fastener.

23. Apparatus according to claim 22, wherein the cross-section of the mandrel shaft is substantially triangular, the flats of the frustoconical portion are generally triangular in shape, the sleeve segments are secant sections of a circle circumscribed about the triangle of the shaft cross-section and the enlarged front portion of the mandrel includes a tapered tip.

24. Apparatus according to claim 1, wherein the mandrel assembly occupies substantially the entire cross-sectional area of the aperture in the fastener for at least a significant portion of the length thereof when the fastener is placed on the mandrel assembly in its unexpanded mode.

25. An apparatus for setting fasteners having apertures therein, which comprises:

a mandrel mounted for movement relative to an anvil surface, said mandrel including a shaft having an enlarged front portion, at least a portion of the shaft being of substantially polygonal cross-section and the enlarged front portion of the mandrel including a generally frustoconical portion of decreasing cross-section between the leading edge thereof and the polygonal cross-section portion of the shaft, sleeve mounted on the mandrel, the front portion of said sleeve being segmented, said sleeve segments having generally flat interiors disposed opposite the sides of the polygonal cross-section portion of the shaft, means for sliding said sleeve relative to the mandrel to and from a position whereat the leading edge of the sleeve is positioned on the enlarged front portion at a point whereat the effective cross-section of the mandrel and sleeve segments are greater than the aperture in the fastener, and

means for driving the expanded mandrel towards the ole circumscribed about the triangle of the shaft crossanvil surface to set the fastener. 26. Apparatus according to claim 25, wherein the cross-section of the mandrel shaft is substantially trian- Includes a tapered gular, the sleeve segments are secant sections of a cirsection and the enlarged front portion of the mandrel 

1. Apparatus for setting fasteners having apertures therein, which comprises: a mandrel assembly adapted to be expanded from an unexpanded mode to an expanded mode mounted for movement relative to an anvil surface, said mandrel assembly being adapted to receive a fastener thereon in its unexpanded mode by effecting relative axial movement between the mandrel assembly and the aperture in the fastener, the mandrel assembly in its unexpanded mode occupying substantially the entire cross-sectional area of the aperture in the fastener when the fastener is received thereon, means for expanding the mandrel assembly to its expanded mode wherein a portion thereof has a cross-section greater than the aperture in the fastener, and means for driving the expanded mandrel assembly toward the anvil surface to set the fastener.
 2. Apparatus according to claim 1, wherein: the mandrel assembly includes a shaft having an enlarged front portion.
 3. Apparatus according to claim 2, wherein the enlarged front portion of the shaft includes a tip tapered to a point from a base having a cross-section larger than that of the shaft and a portion of decreasing cross-section between the base of the tapered tip and the shaft proper.
 4. Apparatus according to claim 2, wherein the means for expanding the mandrel assembly includes a sleeve of resilient material mounted for slidable movement on the mandrel to and from a position whereat the leading edge thereof is mounted adjacent the thickest part of the enlarged front portion thereof, said sleeve being segmented adjacent the leading edge thereof.
 5. Apparatus according to claim 4, wherein: the mandrel shaft is circular in cross-section and the enlarged front portion of the mandrel includes a tapered conical tip and a frustoconical portion of decreasing cross-section between the base of the conical tip and the shaft, and the sleeve is tubular and the segments thereof are in cross-section sections of an annular ring.
 6. Apparatus according to claim 4, wherein: the mandrel shaft is circular in cross-section and the enlarged front portion of the mandrel includes a tapered conical tip and a frustoconical portion of decreasing cross-section between the base of conical tip and said shaft, and said sleeve is tubular and at least portions of the segments thereof are triangular in cross-section, one apex of the triangle being pointed radially outwardly to engage and sever the end of the fastener.
 7. Apparatus according to claim 4, wherein: at least a portion of the mandrel shaft is of triangular cross-section and the enlarged front portion of the mandrel includes a tapered conical tip and a substantially frustoconical portion of decreasing cross-section between the conical tip and the triangular cross-section, the substantially frustoconical section including triangular flats faired into the sides of the triangular shaft, and the sleeve segments are secant sections of a circle circumscribed about the triangle of the shaft cross-section.
 8. Apparatus for setting fasteners having apertures, comprising: a housing including an anvil surface with an aperture therein, a mandrel assembly mounted in said housing and extending out of said aperture, said mandrel assembly being adapted to be expanded from an unexpanded mode to an expanded mode and to receive a fastener thereon in its unexpanded mode for setting by effecting relative axial movement between the mandrel assembly and the aperture in the fastener, the mandrel assembly in its unexpanded mode occupying substantially the entire aperture in the fastener when the fastener is received thereon, means for expanding the mandrel assembly on the side of the fastener away from the anvil surface to a cross-section greater than the diameter of the aperture in the fastener, and means mounted in said housing for driving said expanded mandrel assembly relative to said anvil surface to set the fastener, said means including a cylinder and a piston reciprocal in the cylinder and connected to said mandrel assembly.
 9. Apparatus according to claim 8, wherein: said mandrel assembly includes a shaft having an enlarged front portion, and the means for expanding the mandrel assembly includes a sleeve having a segmented front portion, said sleeve being mounted on the mandrel shaft for movement relative thereto to and from a position whereat at least a portion of the segmented front thereof is adjacent the thickest part of the enlarged front portion of the mandrel shaft such that the thickness of the sleeve segments is added thereto.
 10. Apparatus according to claim 9, wherein the means for moving the sleeve relative to the mandrel shaft includes an enlarged portion provided on said sleeve at the rear thereof and a collar mounted on said mandrel and movable within said enlarged sleeve portion upon the rearward movement of the piston.
 11. Apparatus according to claim 8, wherein: a chamber is provided in said housing between said anvil surface and said cylinder, said chamber communicating with said aperture in the anvil surface, said mandrel assembly includes: a shaft portion extending from the piston through said chamber and out said aperture, an enlarged front portion mounted on the end of the shaft portion extending from the aperture, and a collar portion mounted on the shaft portion in said chamber, said means for expanding the mandrel assembly includes a member mounted for slidable movement with respect to said shaft and having a sleeve portion with a segmented front end extending through said aperture to a position normally adjacent the enlarged front portion of the mandrel shaft and a hollow, enlarged portion connected to said sleeve portion and mounted for movement in said chamber, said hollow enlarged portion enclosing said collar on the shaft, rearward movement of the piston being operable to first expand the mandrel assembly as the enlarged shaft portion is moved relative to the sleeve segments and the latter surround at least a portion of the enlarged front end, adding their thickness thereto, and further rearward movement of the piston being operable to drive the expanded mandrel assembly into the fastener as the collar strikes the rear of the hollow enlarged portion of the expanding member and carries it to the rear along therewith.
 12. Apparatus according to claim 9, wherein said driving means further includes a spring mounted between the back of the piston and the back of the cylinder to bias the enlarged front of the mandrel shaft away from said anvil surface and means for admitting fluid to said cylinder in front of said piston to expand the mandrel assembly by causing movement of the sleeve relative to the mandrel shaft and to drive the expanded mandrel assembly toward said anvil surface.
 13. Apparatus according to claim 11, wherein the shaft portion of the mandrel is circular in cross-section and the enlarged front portion of the mandrel shaft includes an enlarged conical tip and a frustoconical portion of decreasing cross-section between the base of the conical tip and the shaft.
 14. Apparatus according to claim 13, wherein: said chamber is cylindrical, said sleeve is tubular, said segments are arcuate in cross-section and the leading edges thereof are fLared outwardly, and the enlarged portion of the expanding member is tubular with front and rear walls slidable on the mandrel shaft portion, the tubular periphery being slidable in said cylindrical chamber.
 15. Apparatus for setting fasteners having apertures therein, which comprises: a housing, a nose mounted at one end of the housing, said nose including an anvil surface having an aperture therein, a mandrel mounted for reciprocal movement in said housing, means for loading a fastener on the mandrel, means for driving the mandrel through a forward stroke wherein the portion thereof having the fastener loaded thereon extends out the nose, means for expanding the effective cross-section of the end portion of the mandrel beyond that of the fastener aperture after the forward stroke of the mandrel, and means for driving the expanded end of the mandrel toward said anvil surface to set the fastener.
 16. Apparatus according to claim 15, wherein: said mandrel includes a shaft portion and an enlarged front portion, and said means for expanding the mandrel includes a sleeve mounted for slidable movement on the shaft for movement to and from a position adjacent the thickest part of the enlarged front portion of the mandrel.
 17. Apparatus according to claim 15, wherein said nose includes: a plurality of segments hingedly mounted to the housing, and means for biasing said nose segments to a position wereat they are operable to pass the fastener loaded mandrel therethrough from the housing out, but only to pass the mandrel therethrough into the housing, thus providing the anvil surface for the setting of the fastener.
 18. Apparatus according to claim 15, wherein said means for loading a fastener on the mandrel includes: means for supporting the fastener in said housing wherein the aperture therein is in spaced relationship with the mandrel, and means for gating a fastener onto said support in a timed relationship with the reciprocal movement of the mandrel.
 19. Apparatus according to claim 15, wherein said means for driving said mandrel includes a cylinder provided in said housing, a piston mounted on the mandrel and reciprocal in said cylinder, a spring mounted between the back of the cylinder and the back of the piston for driving a portion of the mandrel out of the nose and means for admitting compressed air into the cylinder in front of the piston to set the fastener on the portion of the mandrel extending out of the nose and drive the mandrel portion back inside the housing.
 20. Apparatus according to claim 16, wherein said means for expanding the mandrel further includes: a tubular member mounted to said sleeve at the rear thereof and slidable along therewith on said mandrel, said tubular member including a front and a back, and a collar mounted on said mandrel and within said tubular member wherein initial driving movement of the mandrel effects the expansion of the end portion of the mandrel since the segmented end of the sleeve moves to said position adjacent the thickest portion thereof and when the collar strikes the rear of the tubular member the thus expanded mandrel is driven back into the fastener.
 21. Apparatus according to claim 6, wherein said mandrel shaft conical portion includes a sharp tip for puncturing apertures in work for the receiving of fasteners therein.
 22. An apparatus for setting fasteners having apertures therein, which comprises: a mandrel mounted for movement relative to an anvil surface, said mandrel including a shaft having an enlarged front portion, at least a portion of the shaft being of substantially polygonal cross-section and the enlarged front portion of the mandrel including a generally frustoconical portion of decreasing cross-section between the leading edge thereof and the polygonal cross-section portion of the shaft, said generally frustoconical section including flats faired into the sides of the polygonal shAft, a sleeve mounted on the mandrel, the front portion of said sleeve being segmented, said sleeve segments having generally flat interiors disposed opposite the sides of the polygonal cross-section portion of the shaft, means for sliding said sleeve relative to the mandrel to and from a position whereat the leading edge of the sleeve is positioned on the enlarged front portion at a point whereat the effective cross-section of the mandrel and sleeve segments are greater than the aperture in the fastener, the generally flat interior of the sleeve segments sliding on the flat of the frustoconical portion of the mandrel, and means for driving the expanded mandrel towards the anvil surface to set the fastener.
 23. Apparatus according to claim 22, wherein the cross-section of the mandrel shaft is substantially triangular, the flats of the frustoconical portion are generally triangular in shape, the sleeve segments are secant sections of a circle circumscribed about the triangle of the shaft cross-section and the enlarged front portion of the mandrel includes a tapered tip.
 24. Apparatus according to claim 1, wherein the mandrel assembly occupies substantially the entire cross-sectional area of the aperture in the fastener for at least a significant portion of the length thereof when the fastener is placed on the mandrel assembly in its unexpanded mode.
 25. An apparatus for setting fasteners having apertures therein, which comprises: a mandrel mounted for movement relative to an anvil surface, said mandrel including a shaft having an enlarged front portion, at least a portion of the shaft being of substantially polygonal cross-section and the enlarged front portion of the mandrel including a generally frustoconical portion of decreasing cross-section between the leading edge thereof and the polygonal cross-section portion of the shaft, a sleeve mounted on the mandrel, the front portion of said sleeve being segmented, said sleeve segments having generally flat interiors disposed opposite the sides of the polygonal cross-section portion of the shaft, means for sliding said sleeve relative to the mandrel to and from a position whereat the leading edge of the sleeve is positioned on the enlarged front portion at a point whereat the effective cross-section of the mandrel and sleeve segments are greater than the aperture in the fastener, and means for driving the expanded mandrel towards the anvil surface to set the fastener.
 26. Apparatus according to claim 25, wherein the cross-section of the mandrel shaft is substantially triangular, the sleeve segments are secant sections of a circle circumscribed about the triangle of the shaft cross-section and the enlarged front portion of the mandrel includes a tapered tip. 